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Kinzhal

Kinzhal is a Kotlin Multiplatform library for compile-time dependency injection. The goal is to emulate basic features of Dagger to achieve similar experience in Kotlin Multiplatform projects

Kinzhal is based on Kotlin Symbol Processing (KSP) — the API for lightweight compiler plugins. You’ll need to set up KSP in your project to use Kinzhal

Setup

Add KSP to your plugins section:

plugins {
    id("com.google.devtools.ksp") version "1.5.30-1.0.0"
    kotlin("multiplatform")
    // ...
}

Apply Kinzhal KSP processor:

dependencies {
    ksp("com.daugeldauge.kinzhal:kinzhal-processor:$kinzhalVersion")
}

Add compile-only kinzhal-annotations dependency to your common source set:

kotlin {    
    sourceSets {
        getByName("commonMain") {
            dependencies {
                compileOnly("com.daugeldauge.kinzhal:kinzhal-annotations:$kinzhalVersion")
                // ...
            }
        }

        // Optional workaround for intellij-based IDEs to see generated code. This probably will be fixed someday in KSP plugin.
        // You can replace `jvmName` with any of your target source sets. After the source set is built IDE will start to recognize generate code
        if (System.getProperty("idea.sync.active") != null) {
            kotlin.srcDir("$buildDir/generated/ksp/jvmMain/kotlin")
        }
    }
}

FAQ

What does kinzhal mean?

It’s a russian word for dagger. Yes, K is not a pun

Will this project become deprecated after Dagger releases support for KSP and Multiplatform?

Probably. But we’ll see

What targets are supported?

JVM and most of Kotlin/Native targets. Kotlin/JS is not supported for now (see #4). Please file an issue if you don’t find a target you need

Examples

@AppScope
@Component(modules = [
    NetworkModule::class,
], dependencies = [
    AppDependencies::class,
])
interface AppComponent {
    fun createAuthPresenter(): AuthPresenter
}

interface AppDependencies {
    val application: Application
}

@Scope
annotation class AppScope

class Application

@AppScope
class Database @Inject constructor(application: Application)

class AuthPresenter @Inject constructor(database: Database, lastFmApi: LastFmApi)

class HttpClient

interface LastFmApi

class LastFmKtorApi @Inject constructor(client: HttpClient) : LastFmApi

interface NetworkModule {
    companion object {
        @AppScope
        fun provideHttpClient() = HttpClient()
    }

    fun bindLastFm(lastFmApi: LastFmKtorApi): LastFmApi
}

// somewhere in your app
val component = KinzhalAppComponent(object : AppDependencies {
    override val application = Application()
})

val presenter = component.createAuthPresenter()

See more in the source code

Dagger2 compatibility table

Feature Kinzhal support Notes
@Component
Constructor injection
Field injection 🚫 #1
Component provision functions and properties
@Module ⚠️ Kinzhal has modules but does not have @Module annotation. All classes in component module list are treated as modules. Only object modules with provides=functions and interface modules with binds-functions are allowed
@Provides ⚠️ Kinzhal does not have @Provides annotation. All non-abstract functions in a module are considered to be provides-functions
@Binds ⚠️ Kinzhal does not have @Binds annotation. All abstract functions in a module are considered to be binds-functions
@Scope
@Qualifier
Component dependencies Dependency instances are passed to generated component’s constructor instead of builder functions
@Subcomponent 🚫 #3
You can use component dependency to emulate behaviour of subcomponents
@Reusable 🚫
@BindsInstance 🚫 You can use component dependency to bind instances
Lazy/provider injections 🚫 #2
@BindsOptionalOf 🚫
Multibindings 🚫
Assisted injection 🚫

GitHub

https://github.com/daugeldauge/kinzhal